Apparatus and system for disposing of combustible and waste material

ABSTRACT

The disposal of hydroscopic combustible material, such as scrap wood and bark, needs to be carried on at a temperature of about 600* F. or somewhat lower to prevent flashing off certain volatiles which at or above that temperature level cause the formation of a noxious blue smoke. The system and apparatus is caused to move a large volume of air through a furnace to provide the needed heat for drying the material to a state where it can be consumed by serving as a fuel. The air volume so moved is dust laden, and the apparatus concentrates the dust and particulate material for burning, and effectively mixes the combustible products with cleansed air to produce a source of heat at a controlled temperature level.

United States Patent [1 1 Williams [111 3,826,208 [451 July 30, 1974[75] inventor: Robert M. Williams, Ladue, Mo.

[73] Assignee: Williams Patent Crusher and Pulverizer Company, St.Louis, Mo.

[22] Filed: Aug. 6, 1973 [21] Appl. No.: 385,984

Primary Examiner-Kenneth W. Sprague Attorney, Agent, or FirmGravely,Lieder & Woodruff [57] ABSTRACT The disposal of hydroscopic combustiblematerial, such as scrap wood and bark, needs to be carried on at atemperature of about 600 F. or somewhat lower to prevent flashing offcertain volatiles which at or above that temperature level cause theformation of a noxious blue smoke. The system and apparatus is caused tomove a large volume of air through a furnace to provide the needed heatfor drying the material to a state where it can be consumed by servingas a fuel. The air volume so moved is dust laden, and the apparatusconcentrates the dust and particulate material for burning, andeffectively mixes the combustible products .with cleansed air to producea source of heat at a controlled temperature level.

sum 10F a mQv PAIENTEDNLBOW PAIENIEnJuwmsn APPARATUS AND SYSTEM FORDISPOSING OF COMBUSTIBLE AND WASTE MATERIAL THE BACKGROUND OF THEINVENTION The invention, hereinafter set forth in more detail, isdirected to apparatus for disposing of combustible and waste material,and in which the components of the apparatus are connected up in aunique system for drying the material to prepare it for use as a fueland for also utilizing portions of the material as a fuel to produce thedrying heat for other portions.

The present apparatus relates to disclosure of apparatus in my priorpatent application, Ser. No. 251,182, filed May 8, 1972, and entitledMaterial Reducing System and Apparatus, but is now arranged to makebetter use of the components so that a higher percentage of materialscan be used as a source of fuel to develop drying heat as well as havingthe good result of disposing of the material.

The invention herein has as one of its objects the arrangement of acyclone separator, bag separator and vortex furnace in a system with amaterial reducing mill to reduce the size and, hence, cost of the bagseparator by concentrating material fines in a conduit in by-pass of thebag separator and consuming the fines in the vortex furnace which has abanner capable of using the tines and dust from the bag separator as itsfuel.

It is another object of this invention to provide a vortex furnace forburning the material fines as its source of heat, and to control theamount of air supplied to support combustion in the range of aboutpercent excess oxygen, and to allow the bag separator to be sized forthe discharge of moisture laden air or gas from the system.

A further object of this invention is to apply a vortex furnace as theheat source and to make use of the cyclonic action in the furnace forretaining oversized particles in the combustion flame until completelyconsumed, and to have the vortex furnace serve as a trap for unburnableswhich are then periodically discharged.

Still another object is to apply the apparatus in a system where afteran outside source of gas or oil fuel has established a combustion flamecondition in the vortex furnace, that fuel source can be cut off and thecombustion cycle continued on the combustibles extracted from thematerial introduced to the system.

Another object of this invention is to provide the primary separator inthe system with means that can control the extraction of fines in thematerial admitted to the cyclone, and cause the fines to pass out withthe normal air flow, thereby enhancing the separation of fines from theproduct that is discharged at the bottom outlet from the cyclone andcollected for treatment to convert it to a fuel or for other purposes.

BRIEF DESCRIPTION OF THE DRAWINGS The apparatus which is exemplary ofthe present invention is shown generally in schematic arrangements toillustrate the manner in which system components are caused to cooperateto achieve the objects above set forth, and wherein:

FIG. I is a schematic view of one embodiment of apparatus and system fordisposing of combustible and waste material such as wood, bark, coal,and the like;

FIG. 1A is a fragmentary sectional view taken at line lA-lA of FIG. 1;

FIG. 2 is a fragmentary sectional view of a rotary valve providing meansfor leaking ambient air into the primary separator to increasethe'amount of fines passing over with air;

FIG. 3 is a schematic view of only a portion of a complete system, asdepicted in FIG. 1, for the purpose of disclosing a modified arrangementof apparatus; and

FIG. 4 is a schematic view of a system of apparatus similar to FIG. 1,but differing in the character of reducing mill for the material.

DETAILED DESCRIPTION OF THE APPARATUS Reference will now be directed toFIG. 1 of the accompanying drawing where there is schematically shownapparatus for practicing the invention heretofore briefly summarized.The primary arrangement of apparatus includes a suitable conveyor 10 forbringing the wood chips, bark, coal, and other material to be reduced toa hopper 11 which directs the material into a feed unit 12 ofconventional feed screw construction having a driving motor 12A. Anyfeed means can be used, but it is preferred in this instance to use ascrew feed mechanism and to operate the unit 12 with the hopper 11continually filled so as to exclude as much as possible the inflow ofambient air. The screw feed unti l2 delivers the material into anupwardly directed passage 13 which opens at the upper end into anexpansion chamber 14. The passage l3'includes a portion having a venturithroat 15 which is both an outlet and an inlet for a suitable mill Mhaving a rotor 17 which is operable to run in either direction.

The expansion chamber 14 above the passage 13 opens into a conduit 18which delivers material tangentially into a conventional cycloneseparator 19 where the material flowing in the airstream is separatedout through a rotary valve 20 and is collected in a suitable bin B,while the air carrying dust and fines is delivered through conduit 21 tothe suction side of a blower 22. The conduit 23 from the outlet of theblower 22. The conduit 23 from the outlet of the blower 22 returns theair to the mill M at passage 13 below the venturi 15.

The apparatus of FIG. 1 is designed to reduce friable material such aswood chips and bark to a uniform product which is delivered into the binB. The wood chips and bark, delivered to the hopper 11, are conveyed bythe screw feed unit 12 into the passage 13. The blower 22 is, of course,operated to create a circulation or flow of air upward through theventuri l5 and around the circuit including the expansion chamber 14,the cyclone separator 19 and the return conduit 21 to the blower 22. Adamper 24 is operably mounted in the conduit 21 near the suction inletof the blower 22 so that the velocity of the circulating air through theventuri 15 can be regulated as desired. The material delivered to thepassage 13 contains a certain percentage of dust and fines along withthe larger chips, chunks and pieces. The flow through'the venturi 15 is,therefore, regulated by the damper 24 so that the fines are caused tofloat upwardly into the expansion chamber 14 while gravity causes thelarger and heavier particles and pieces to fall through the venturi 15where it is ground and reduced by the hammer rotor 17 and flungbackwardly through the venturi 15, and exhausted by the flow beingdelivered through the conduit 23 below the venturi 15. The flow throughthe passage 13 and expansion chamber 14 will contain a fluid mediumcomposed of dust and fines suspended in air and this medium willtraverse the conduit 18 to the cyclone separator 19 where a desiredseparation occurs and airborne dust and fines are delivered through thetop outlet conduit 21 while the material separated out is collected inthe bin B.

Control over the amount of dust and fines carried out of cycloneseparator 19 through the air exhaust box 25 is provided by means of ahinged skimmer vane 26 (FIG. 1A) which may be adjustably positioned moreor less into the vortex flow entering the cyclone 19 from the inletconduit 18. The vane 26 is positionable to skim out the finer or smallerportions of the material entering the cyclone 19 for flow through theexhaust box 25 and into the exit conduit 21 and delivery to the blower22. The delivery side of blower 22 is subject to suction at theconnection of conduit 27 which is connected to a bag separator 28, andthe separator 28 is under suction from blower 29 through conduit 30. Theportion of the material skimmed out by the vane 26 for delivery to theseparator 28 and eventual delivery through a rotary valve 31 to a screwconveyor device 32 driven by motor 33 to conduit 34 is conducted to theburner 35 of a furnace 36. Thus the fines extracted by the skimming vane26 will be consumed in the fur nace 36 to act as fuel and furnish heatfor drying purposes. At the same time selective portions of the materialdelviere'd to the cyclone separator 19 will be collected in the closedbin B.

FIG. 1A illustrates one means for selective extraction of the dust andfines from the chamber of the cyclone separator 19. If the skimming vane26 is not desired, the same effect can be obtained by creating theunusual leakage of ambient air into the cyclone chamber through therotary valve 20. For this purpose, the valve (FIG. 2), driven bysuitable motor means A, has its multi-bladed rotor 20A enclosed betweenopposed side walls 208 adjustably mounted by bolts 20C to the sideplates 20D (one being seen) of the valve housing mounted at the apex ofthe cyclone chamber 19A. The side walls 208 can be adjusted toward oraway from the path of motion of the valve blades 20A to vary the ambientair leakage into the cyclone chamber apex. The air leaking into thecyclone is greatest, and the result is that dust and fines reaching theapex zone are whisked upwardly to the outlet conduit 18 while thedesired larger particles are exhausted through the rotary valve to thebin B.

Returning to FIG. 1, the apparatus is arranged with a furnace 36 whichis provided with a standard wood fuel burner 35 to which an outsidesource of oil or gas fuel is connected at pipe 37. Combustion air issupplied into conduit 34 by conduit 38 from the blower 39. The furnace36 has a cyclone chamber 40 lined with a suitable refractory. Thecyclone chamber has an inlet at conduit 41 to deliver the hot gasesthrough conduit 43 into conduit 23 at a junction adjacent the mill M.The furnace inlet 41 receives a supply of combustible material fromconduit 44 which is connected to conduit 27 in by-pass of the bagseparator 28, and a suitable valve 45 is placed in the by-pass conduit44. A supply of combustion air for the furnace is obtained throughconduit 46 controlled by valve 47. The amount of air admitted Inemploying the furnace 36 with a cyclone chamber 40, the non-burnables,such as sand, rock and the like, work their way along the bottom walland can be exhausted through a dump chute 50 having a rotary valve 51.The material so dumped can be collected by a suitable belt conveyor 52for movement to a disposal station.

The system of FIG. 1, is especially unique because it allows the use ofa smaller and less expensive bag separator 28 than would otherwise beneeded, and it allows the by-passing in conduit 44 of fines and the liketo be used as fuel in the vortex of the cyclone chamber. Further, thesystem provides a way to dispose of the fines and dust extracted by thebag separator as a source of fuel for the burner 35, thereby gainingheat for drying purposes. The burner 35 does not permit the passage oflarge amounts of air and requires the fuel to be burned in a controlledamount of air which is normally in the range of fourteen percent excessoxygen.

The operation of the system of FIG. 1 is to produce drying heat for theincoming material, and to use portions of that material as a fuel toproduce the heat for drying the product portions not used in this systemas a fuel. Thus, the incoming material at passage 13 undergoes a firstsorting step where the tines capable of floating in a controlled airstream are moved along to a cyclone separator 19. The larger portions ofthe incoming material pass by gravity to the mill M for reduction beforebeing returned to passage 13. The second sorting step takes place in thecyclone separator 19 where the dust and fines are intentionally passedinto the cyclone outlet conduit 21, thereby keeping this portion of thematerial out of the product portion that is discharged to the bin B. Thesecond sorting step is accomplished either by using the adjustableskimmer vane 26 (FIG. 1A) to direct the dust and fines into conduit 21through the exhaust box 25, or by closing the vane 26 and adjusting oneor both of the rotary valve side walls 203 (FIG. 2) to allow leakage ofambient air through the product outlet to sweep the dust and finesupwardly in the cyclone 19 to the exhaust box 25. The product collectedin bin 20 may be further treated to convert it to a gaseous fuel.

The flow of dust and fines in the carrier air stream in conduit 21 andblower 22 is subjected to the suction effect at the connection ofconduit 27 to the outlet conduit 23 of blower 22. The dust and fines aredrawn off in conduit 27 to the bag separator 28 by reason of theoperation of blower 29 connected to the bag separator. The air andmoisture therein is discharged to atmosphere at conduit 48, and thefines and dust are discharged by the bottom rotary valve 31 into a screwconveyor 32 which delivers the material into conduit 34. The materialflow in conduit 34, along with ambient air from blower 39 is fed to theburner 35 of the furnace 36. The burner 36 is of the type that does not7 allow the passage of a large quantity of air, so the fuel is,therefore, burned in a controlled air volume, normally in the range ofabout 14 percent percent excess oxygen. Because of this feature of theburner 36, and the permissible reduction in size of the bag separator28, about percent of the air, fines, and dust is bypassed at conduit 44directly to the furnace inlet 41. The entrance of air, fines, and dustis directed tangentially of the furnace wall, and refractory lining isused to reduce abrasion and heat effect on the furnace shell. Thefurance 36 acts like a cyclone and the dust and fines are concentratedtoward the flame issuing from the burner where they are consumed toproduce the heat that is conveyed by the air out to conduit 43. The exitheat level is maintained at about 600 F. by adjusting the air admittedat conduit 46 past valve 47.

It has been noted that the material carried into the furnace 36 containsnon-combustible material. This material is moved by the cyclone actionto the exhaust chute 50 where it is discharged by the rotary valve 51onto the carry-over conveyor 52. Also, any oversize particles ofmaterial received therein remain for the time required to effectcomplete combustion, as such material is effectively trapped by thecyclone action and moved into the flame area under violent mixingconditions. When the burner flame has been established in the furnace36, the outside fuel source is cut off, and the dust and fines needed tocontinue combustion can be supplied in sufficient amounts by adjustingthe skimmer vane, or by adjusting the rotary valve side walls 20B to thedesired leakage condition.

A modification of the apparatus of FIG. 1 is seen in FIG. 3 wheresimilar parts and components are similarly enumerated so that only theadditional parts and components will be described. As shown the heatoutlet from the cyclone furnace 36 is conduit 43A which is connecteddirectly to a cyclone chamber 53 where the heat level can be moreclosely controlled, and any particulate material carried out of thefurnace 36 will have a chance to separate out and be discharged throughrotary valve 54. The control of the temperature level is partly obtainedby leading a portion of the exhaust flow of blower 29 through conduit55, controlled by valve 56, to the cyclone chamber 53. The hot gas (air)issuing from the chamber 53 is led by conduit 57 into a junction (notseen but similar to FIG. 1) with conduit 23 of blower 22 adjacent themill M.

In the operation of the system of apparatus seen in FIG. 1, thetemperature of the hot gases (air) at the furnace outlet conduit 43 isdesired to be of the order of 600 F. so as to be below the flashtemperature of the volatiles in the wood waste. The temperature isregulated by the quantity of air brought in at conduit 46. In FIG. 2,the cyclone furnace 36 can operate at a higher temperature for betterconsumption of the burnable material. While the temperature of the gasesissuing from furnace 36 at conduit 43A can be considerably higher than600 R, such gases are led into the chamber 53 and mixed with clean airfrom conduit 55 so the final gas temperature at conduit 57 is at thedesired level. Further, the cyclone action in chamber 53 throws out ofthe gases substantially all of the particulate material that might becarried out of the furnace.

Turning to FIG. 4, the system of apparatus is similar to that shown anddescribed in FIG. 1, except that the hammer mill M has now been replacedwith a rotary mill RM. This modified system is suitable for handlingsuch material as coal. The difference is in the way the hot gases (air)are fed to the mill RM. A rotary or roller mill RM has the grindingrolls 58 connected to a vertical shaft 59 driven through a reductiongear train 60 and a belt drive 61 from the motor 62. The motor 62 anddrive is disposed in a suitable foundation 63 which supports the scrollcasing 64 surrounding the grinding chamber of the mill RM. The casing 64has a plurality of inlets 65 opening to the grinding chamber, while thecasing 64 is connected to the end of conduit 23. The hot gas supplyconduit 43 is joined into conduit 23 adjacent the inlet 65. The forcedflow of hot gases in the scroll casing 64 flows intothe grinding chamberand carries the material upwardly past the drive shaft 59 and into theventuri throat 15 of passage 13 in opposition to the fall of the heavymaterial through the venturi throat.

The mill RM is provided with a dump chute 66 opening from the bottom ofthe grinding chamber to the outside of the foundation 63 where thematerial incapable of being easily reduced is collected on a suitableconveyor 67. A valve 68 normally closes the chute outlet to avoidimpairing the function of the flow of air to the venturi throat 15.

From the foregoing description it should be apparent that the apparatus,in any of its embodiments, is adapted for the efficient disposal ofcombustible material without generating and releasing to the atmospherenoxious fumes, or polluting the atmosphere with particulate material. Inthe broad view of the apparatus, it is directed to means for disposingof combustible material by processing the material in a firstcirculating system which includes a material reducing mill, a cycloneseparator and a blower for circulating air as the carrier medium for thereduced material and for dust and fines that are inherently associatedtherewith. The apparatus also includes a second circulating systemconnected into the first system and including a separator for extractingdust and fines, a furnace in which the dust and fines are consumed bycombustion, and means for returning the heat of the combustion to thefirst system for effectively drying the moisture that may be containedtherein. The apparatus is provided in the second circulating system withmeans for discharging the moisture to ambient atmosphere at atemperature that is below the level that could cause noxious fumes to bereleased to atmosphere.

This invention is intended to cover all changes and modifications of theexample of the invention herein chosen for purposes of the disclosure,which do not constitute departures from the spirit and scope of theinvention.

What is claimed is:

1. In apparatus for disposing of combustible material the improvement ofa mill for reducing the size of the material, conduit means to feedmaterial into said mill, an air circulating system connected across saidmill and conduit means to move reduced material and dust and fines awayfrom said mill, separator means connected into said circulating systemto remove the fines and dust from the reduced material, a drying heatproducing system connected into said circulating system between saidseparator and mill for effecting the drying of the material in said aircirculating system, said heat system including a dust and finesseparator, a furnace, fuel supply means to initiate furnace operation,means connected between said dust and fines separator and said furnaceto supply dust and fines into said furnace for combustion to continuefurnace operation, the heat of said furnace being delivered to saidmill, and means in said heat producing system to supply ambient air toregulate the temperature of the heat of said furnace.

2. The apparatus of claim 1 wherein first mentioned separator includesmeans for discharging reduced material from the air circulating systemand for removing the tines and dust from the reduced material.

3. The apparatus of claim 2 wherein said means for removing the finesand dust is constituted by a skimming vane in said first mentionedseparator.

4. The apparatus of claim 2 wherein said means for removing the finesand dust is constituted by said reduced material discharge means havinga housing with a rotary valve operable in said housing, and anadjustable wall enclosing siad rotary valve with a leak passage forambient air flow into said first mentioned separator.

5. In apparatus for disposing of combustible material and for producinga product substantially free of dust and fines, the improvement whichconsists of: a first circulating system having a material inlet passageconnected into a material reducing mill and leading to a cycloneseparator to deliver reduced material, fines and dust to said cycloneseparator, a primary blower having a suction connection to said cycloneseparator and a delivery connection to said miil and inlet passage, saidprimary blower causing the movement of reduced material, fines and dustinto said cyclone separator, valve means connected to said cycloneseparator to discharge the reduced material as the product, and means atsaid cyclone separator to remove the fines and dust from the reducedmaterial discharged by said valve means; a second circulating systemhaving an inlet connection adjacent said blower delivery connection andan outlet adjacent said reducing mill, said second system including asecondary blower, a bag separator connected on one side into the suctionof said secondary blower and connected on the other side to said inletconnection for said second system, said bag separator having an outletfor the fines and dust, a furnace having a combustion chamber and a fuelburner connected to said chamber, means to conduct the fines and dustfrom said bag separator outlet into said fuel burner, means in by-passof said bag separator to supply fines and dust into said combustionchamber for burning as a fuel, and means connecting said combustionchamber to said first circulation system adjacent said mill to supplyheat for drying the combustible material introduced at said inletpassage.

6. ln apparatus for disposing of combustible material the improvementwhich consists in: a first circulating system having a blower to propelair as a carrier medium in said first system, a material reducing millin said first system, means to feed material into said first systemadjacent said mill for reduction in said mill and flow with the air insaid first system, a cyclone separator in said first system having anoutlet connected into the suction side of said blower and an inletconnected to receive reduced material from said mill along with finesand dust in said first system, and said cyclone separator having adischarge for reduced material that is substantially free of fines anddust; and a second circulating system having an inlet connectionadjacent the delivery side of said blower, separator means for fines anddust connected to said second system inlet, a second blower hving asuction connection at said separator means and an outlet to atmosphere,a furnace connected into said second system beyond said separator meansin the flow direction to receive the fines and dust drawn into saidsecond system by said second blower and dispose of them by combustion,and conduit means connected to said furnace and to said first systemadjacent said mill to deliver furnace heat into said first system formaterial drying purposes.

7. The apparatus of claim 6 wherein means is connected into said furnaceto admit ambient air to regulate the temperature of the furnacedelivery.

8. The apparatus of claim 6 wherein said conduit means to deliver heatinto said first system includes a cyclone chamber having its inletconnected to said furnace and its outlet connected to said first system,and

a conduit connection between said second blower outlet and said cyclonechamber to supply air for regulating the temperature of the air deliveryinto said first system.

9. The apparatus of claim 6 wherein said cyclone separator includesvalve means in said discharge to release the reduced material, and othermeans to effect the separation of the fines and dust from the reducedmaterial released by said valve means.

10. The apparatus of claim 9 wherein said other means includes a casingfor said valve means, and a movable component for said casing to producea leak age passage through said valve means fro the ingress of ambientair.

i i I

1. In apparatus for disposing of combustible material the improvement ofa mill for reducing the size of the material, conduit means to feedmaterial into said mill, an air circulating system connected across saidmill and conduit means to move reduced material and dust and fines awayfrom said mill, separator means connected into said circulating systemto remove the fines and dust from the reduced material, a drying heatproducing system connected into said circulating system between saidseparator and mill for effecting the drying of the material in said aircirculating system, said heat system including a dust and finesseparator, a furnace, fuel supply means to initiate furnace operation,means connected between said dust and fines separator and said furnaceto supply dust and fines into said furnace for combustion to continuefurnace operation, the heat of said furnace being delivered to saidmill, and means in said heat producing system to supply ambient air toregulate the temperature of the heat of said furnace.
 2. The apparatusof claim 1 wherein first mentioned separator includes means fordischarging reduced material from the air circulating system and forremoving the fines and dust from the reduced material.
 3. The apparatusof claim 2 wherein said means for removing the fines and dust isconstituted by a skimming vane in said first mentioned separator.
 4. Theapparatus of claim 2 wherein said means for removing the fines and dustis constituted by said reduced material discharge means having a housingwith a rotary valve operable in said housing, and an adjustable wallenclosing siad rotary valve with a leak passage for ambient air flowinto said first mentioned separator.
 5. In apparatus for disposing ofcombustible material and for producing a product substantially free ofdust and fines, the improvement which consists of: a first circulatingsystem having a material inlet passage connected into a materialreducing mill and leading to a cyclone separator to deliver reducedmaterial, fines and dust to said cyclone separator, a primary blowerhaving a suction connection to said cyclone separator and a deliveryconnection to said mill and inlet passage, said primary blower causingthe movement of reduced material, fines and dust into said cycloneseparator, valve means connected to said cyclone separator to dischargethe reduced material as the product, and means at said cyclone separatorto remove the fines and dust from the reduced material discharged bysaid valve means; a second circulating system having an inlet connectionadjacent said blower delivery connection and an outlet adjacent saidreducing mill, said second system including a secondary blower, a bagseparator connected on one side into the suction of said secondaryblower and connected on the other side to said inlet connection for saidsecond system, said bag separator having an outlet for the fines anddust, a furnace having a combustion chamber and a fuel burner connectedto said chamber, means to conduct the fines and dust from said bagseparator outlet into said fuel burner, means in by-pass of said bagseparator to supply fines and dust into said combustion chamber forburning as a fuel, and means connecting said combustion chamber to saidfirst circulation sYstem adjacent said mill to supply heat for dryingthe combustible material introduced at said inlet passage.
 6. Inapparatus for disposing of combustible material the improvement whichconsists in: a first circulating system having a blower to propel air asa carrier medium in said first system, a material reducing mill in saidfirst system, means to feed material into said first system adjacentsaid mill for reduction in said mill and flow with the air in said firstsystem, a cyclone separator in said first system having an outletconnected into the suction side of said blower and an inlet connected toreceive reduced material from said mill along with fines and dust insaid first system, and said cyclone separator having a discharge forreduced material that is substantially free of fines and dust; and asecond circulating system having an inlet connection adjacent thedelivery side of said blower, separator means for fines and dustconnected to said second system inlet, a second blower hving a suctionconnection at said separator means and an outlet to atmosphere, afurnace connected into said second system beyond said separator means inthe flow direction to receive the fines and dust drawn into said secondsystem by said second blower and dispose of them by combustion, andconduit means connected to said furnace and to said first systemadjacent said mill to deliver furnace heat into said first system formaterial drying purposes.
 7. The apparatus of claim 6 wherein means isconnected into said furnace to admit ambient air to regulate thetemperature of the furnace delivery.
 8. The apparatus of claim 6 whereinsaid conduit means to deliver heat into said first system includes acyclone chamber having its inlet connected to said furnace and itsoutlet connected to said first system, and a conduit connection betweensaid second blower outlet and said cyclone chamber to supply air forregulating the temperature of the air delivery into said first system.9. The apparatus of claim 6 wherein said cyclone separator includesvalve means in said discharge to release the reduced material, and othermeans to effect the separation of the fines and dust from the reducedmaterial released by said valve means.
 10. The apparatus of claim 9wherein said other means includes a casing for said valve means, and amovable component for said casing to produce a leakage passage throughsaid valve means fro the ingress of ambient air.